Inter-Cell Interference in Noncooperative TDD Large Scale Antenna Systems

TLDR

Previous work established the asymptotic behavior of the SINR in large‑antenna cellular networks. The paper investigates cellular network performance with infinitely many antennas, deriving exact SINR expressions and proposing a method to avoid simultaneous pilot transmissions from adjacent cells. The authors derive closed‑form SINR formulas for downlink and uplink, implement a scheduling scheme to eliminate simultaneous pilot transmissions, and analyze power‑allocation strategies to improve interference ratios. The study finds that pilot‑sequence contamination occurs with simultaneous non‑orthogonal transmissions, but power‑allocation and scheduling techniques can yield over 15 dB SINR gains and roughly 18‑fold rate improvements in simulations.

Abstract

In this paper we study the performance of cellular networks when their base stations have an unlimited number of antennas. In previous work, the asymptotic behavior of the signal to interference plus nose ratio (SINR) was obtained. We revisit these results by deriving the rigorous expression for the SINR of both downlink and uplink in the scenario of infinite number of antennas. We show that the contamination of the channel estimates happens whenever a pilot sequence is received at a base station simultaneously with non-orthogonal signals coming from other users. We propose a method to avoid such simultaneous transmissions from adjacent cells, thus significantly decreasing interference. We also investigate the effects of power allocation in this interference-limited scenario, and show that it results in gains of over 15dB in the signal to interference ratio for the scenario simulated here. The combination of these two techniques results in rate gains of about 18 times in our simulations.